Chemotherapy treatment as maximum opportunity for cancer cure or control when maximum drug doses can be administered to patients. Adequate control of nausea side effects allows maximum chemotherapy drug dosages to be given. Despite improvements in antiemetic treatments, over 70% of patients continue to experience nausea during chemotherapy. Data from the current continuation show: i) substantial involvement of the parasympathetic branch of the autonomic nervous system (ANS) in nausea development and expression; ii) vagal tone measured before treatment is given shows promise in predicting the subsequent occurrence of chemotherapy induced nausea. Proposed studies will answer five specific research questions: 1) Vagal activity based on the standard deviation of differences in successive heart beats (R-R intervals) will be compared with patient self-report of nausea to answer the question "Do patients who develop chemotherapy induced nausea show a decrease in parasympathetic activity before the symptom?" 2) Ambulatory measures of gastric activity through spectral analysis of electrogastric activity will be compared with a patients' self-report to answer the question "what is the temporal relationship between the gastric tachyrhythmia and patient report of nausea?" 3) Comparison of vagal tone taken under paced breathing prior to the administration of chemotherapy drugs will be compared with patients' self- report to answer the question "Can measures of vagal tone predict subsequent chemotherapy treatment-induced nausea?" 4) Measures of vagal tone will be compared in patients who do and do not develop anticipatory nausea and delayed nausea to answer the question "Do vagal characteristics predict anticipatory nausea or delayed nausea?" 5) Repeated assessment of chemotherapy patients at treatments 1,3,6 and then 3 and 6 months after chemotherapy ends will answer the questions "Are changes in vagal activity resulting from chemotherapy drugs reversible?" Current data come from 36 single gender subjects (women) with a single drug treatment (cisplatin or its analogue carboplatin) for a single diagnosis (ovarian cancer). Proposed research will expand and examine the generalizability of current findings by studying 200 patients of both genders with a variety of diagnoses given a variety of chemotherapy drugs. Anticipated results could have methodological and theoretical applications in antiemetic trials and studies of individual differences in self- reporting symptoms. Better understanding of potential nausea mechanisms could also help predict patients at risk of severe nausea and lead to improved pharmacologic and behavioral control of nausea resulting from chemotherapy or other situations such as motion sickness and pregnancy.